1. Field of the Invention
This invention is directed to purification of urania materials. Finely divided urania scrap materials are subjected to sintering conditions at high temperatures of greater than 1600.degree. C. in a freely flowing hydrogen atmosphere to remove impurities such as Si, Fe, Ni, Sn, Cu, Na and Pb.
2. Background Information
Poor uranyl nitrate filtration during dissolution of certain blends of urania powder for clean scrap is an ongoing problem. Expensive decontamination and recovery steps like solvent extraction have plagued the industry for years. Attempts to solve the problems via re-oxidation and extra calciner treatment have met with only limited success.
Beese, U.S. Pat. No. 2,768,873, discloses a method of purifying uranium wherein uranium oxide is ground, placed in a crucible and introduced into a furnace at 1200.degree. C. in an air atmosphere in order to volatize boron impurities. The Beese patent addresses the removal of only one element, boron, and that process is done in an oxidizing atmosphere only.
Foltz, U.S. Pat. No. 3,140,151, discloses a method of reprocessing sintered irradiated UO.sub.2 by subjecting it to a number of oxidizing and reducing cycles. The Foltz patent addresses processing only irradiated urania materials with substantially lower temperatures and alludes to removal of only the more volatile elements/radionucleides. It also makes substantial use of intermediate oxidizing conditions.